Electrically heated roller arrangements

ABSTRACT

An electrically heated roller has an electric coil mounted in the core member of the assembly. The core has a plurality of slots extending inwardly from the periphery of the core member in a radial direction with respect to the coil, and parallel to the axis of the coil. The slots serve to reduce local eddy currents, and to provide air cooling passages.

United States Patent France [4 1, Mar. 28, 1972 [54] ELECTRICALLY HEATED ROLLER [56] References Cited ARRANGEMENTS UNlTED STATES PATENTS [721 lnvenm Harwwd, 8mm, 3,187,150 6/1965 France ..2l9/l0.6l

gland 3,435,171 3/1969 Lohest [73] Assignee: T.T.M. (Research) Limited, Oldham, Lan- 3,487,187 12/ i969 Martens et a1 ..219/l0.6l

cashire, England [22] Filed: 14 1970 Primary Examiner-J. V. Truhe 7 Assistant Examiner-Hugh D. .laeger [21] APPLNO" 9 AnorneyWatson,Cole,Grindle& Watson I 30) Foreign Application Priority Data [57] ABSTRACT Dec. 15, Great Britain An electrically heated roller has an electric coil mounted in the core member of the assembly. The core has a plurality of slots extending inwardly from the periphery of the core 11 158 Field of Search ..2l9/l0.61,469 member a rad! respect m the and parallel to the axis of the coil. The slots serve to reduce local eddy currents, and to provide air cooling passages.

8 Claims, 2 Drawing Figures ELECTRICALLY HEATED ROLLER ARRANGEMENTS The present invention relates to electrically heated roller arrangements.

in the specification of our British Pat. No. 989349, there is described a heated roller arrangement for use in the processing of synthetic yarns or filaments. The arrangement comprises a magnetizable cylindrical shell over which the yarn to be heated is passed. The shell is fixedly mounted on one end of a rotatable driving shaft so that the skirt portion of the shell extends along the shaft in concentric relation thereto. Inside the skirt portion of the shell is a stationarily arranged magnetic core upon which is wound an electric coil to be supplied with energizing current from an alternating current source. The magnetic flux generated in the core by the passage of the energizing current through the coil passes through the shell to produce heat therein. The core on which the coil is wound is made from a plurality of laminations in order to reduce the heating effect of local eddy currents in the core. A laminated core is however expensive to produce and presents difficulties in manufacture and assembly.

An object of the present invention is to provide a magnetic core which retains advantages of the laminated core but is of less complex construction.

According to one aspect of the present invention, there is provided an electrically heated roller arrangement for use in the processing of synthetic yarns or filaments, comprising a rotatable magnetizable shell in the form of a solid of revolution, over which the yarn to be heated is passed, a magnetic core member arranged within the shell and an electrical energizing coil which is wound in a peripheral recess in the core member in concentric relation to the axis of revolution of the shell and which generates by the passage of energizing current therethrough a magnetic flux which passes through the shell to produce heat therein, said core member having a plurality of slots extending inwardly from the periphery of the core member in a radial direction with respect to the coil and parallel to the axis of the coil.

Preferably, the slots project radially inwardly beyond the internal diameter of the energizing coil, with each slot extending also axially throughout the length of the core member to provide a passage for air through the core member and along the inside of the energizing coil.

in a preferred embodiment of the invention the shell is a cylindrical or substantially cylindrical shell, the core member is of cylindrical or substantially cylindrical form and said recess is a circumferential recess formed in the outer cylindrical surface of the core member.

An embodiment of the invention will now be described with reference to the accompanying drawing in which:

FIG. 1 is a sectional side elevation of a heated roller arrangement according to the invention, and

F 10. 2 is a section taken on the line [1-11 in FIG. 1.

Referring to the drawing, the heated roller arrangement shown comprises a shaft 1 rotatable with a bearing 2 fixed in a housing 3. A roller 4 is closed at one end where it is fixed to the projecting end of the shaft 1 and has a skirt portion 5 extending back along the shaft and concentrically with respect thereto. Enclosed within the skirt portion is a magnetizable core 6 which has a circumferential recess 7 which houses an electric coil 8. The core 6 is stationarily mounted on a sleeve 9 which is secured to the housing 3 by screws 10.

The coil 8 is, in operation, supplied with energizing current from an alternating current source, the magnetic flux generated in the core 6 by the passage of the energizing current through the coil passing into the shell 5 and producing a heating effect therein.

The core 6 has, as best seen in FIG. 2, a plurality of longitudinal slots 11 extending radially inwardly from its periphery to a position beyond the internal diameter of the coil so as to provide air gaps 12. The slots 11 serve to reduce local eddy currents in the core by ensuring that the flux paths extend along planes passing through the axis of rotation of the shaft 1 and furthermore serve to keep down the temperature of the core and the coil 8 by providing passages for air through the core 6 and along the inside of the coil 8.

Further cooling of the elements contained within the skirt portion 5 of the roller 4 is effected by an impeller 13 fitted to the shaft 1. In operation, the impeller 13 creates a circulation of air within the shell, which further assists in cooling the core 6 and the coil 8.

The electric heating control arrangement may be as described in the specification of our British Pat. No. 989,349.

What I claim as my invention and desire to secure by Letters Patent is:

1. An electrically heated roller arrangement for use in the processing of synthetic yarns or filaments, comprising a rotatable magnetizable shell in the form of a solid of revolution for heating said synthetic filaments, a magnetic core member mounted within said shell and having a peripheral recess, an electrical energizing coil wound in said peripheral recess in concentric relation to the axis of revolution of said shell and for generating a magnetic flux which passes through said shell to produce heat therein, and said core member having a plurality of slots extending inwardly from the periphery of the length of the core member in a radial direction with respect to the coil and parallel to the axis of the coil beyond the internal diameter thereof to provide a passage through said core member and along the inside of said energizing coil.

2. An arrangement according to claim 1 wherein said shell is substantially cylindrical, the core member is substantially cylindrical, and wherein said recess is a circumferential recess formed in the outer cylindrical surface of said core member.

3. An arrangement according to claim 2, wherein said shell is mounted concentrically on a supporting shaft and said magnetic core member is mounted to be stationary within said shell.

4. An arrangement according to claim 3, wherein said shell is open at one end and closed at the other end, said supporting shaft comprises a rotatable driving shaft, and said closed end of the shell is fixedly mounted on one end of the shaft so that a skirt portion of the shell extends along the shaft.

5. An arrangement according to claim 4, wherein said core member is mounted to be stationary on a fixed sleeve through which said driving shaft passes.

6. An arrangement according to claim 4, wherein said rotatable driving shaft includes an impeller producing a circulation of air within said shell.

7. An arrangement according to claim 6, wherein said impeller is formed by longitudinally extending radial impeller blades arranged in spaced relation around said driving shaft.

8. An arrangement according to claim 7 wherein said core member is mounted in cantilever fashion on said sleeve, and said impeller blades extend along said shaft to an exposed cantilevered portion of said core member. 

1. An electrically heated roller arrangement for use in the processing of synthetic yarns or filaments, comprising a rotatable magnetizable shell in the form of a solid of revolution for heating said synthetic filaments, a magnetic core member mounted within said shell and having a peripheral recess, an electrical energizing coil wound in said peripheral recess in concentric relation to the axis of revolution of said shell and for generating a magnetic flux which passes through said shell to produce heat therein, and said core member having a plurality of slots extending inwardly from the periphery of the length of the core member in a radial direction with respect to the coil and parallel to the axis of the coil beyond the internal diameter thereof to provide a passage through said core member and along the inside of said energizing coil.
 2. An arrangement according to claim 1 wherein said shell is substantially cylindrical, the core member is substantially cylindrical, and wherein said recess is a circumferential recess formed in the outer cylindrical surface of said core member.
 3. An arrangement according to claim 2, wherein said shell is mounted concentrically on a supporting shaft and said magnetic core member is mounted to be stationary within said shell.
 4. An arrangement according to claim 3, wherein said shell is open at one end and closed at the other end, said supporting shaft comprises a rotatable driving shaft, and said closed end of the shell is fixedly mounted on one end of the shaft so that a skirt portion of the shell extends along the shaft.
 5. An arrangement according to claim 4, wherein said core member is mounted to be stationary on a fixed sleeve through which said driving shaft passes.
 6. An arrangement according to claim 4, wherein said rotatable driving shaft includes an impeller producing a circulation of air within said shell.
 7. An arrangement according to claim 6, wherein said impeller is formed by longitudinally extending radial impeller blades arranged in spaced relation around said driving shaft.
 8. An arrangement according to claim 7 wherein said core member is mounted in cantilever fashion on said sleeve, and said impeller blades extend along said shaft to an exposed cantilevered portion of said core member. 